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United States Patent |
5,093,347
|
Graneto
,   et al.
|
March 3, 1992
|
3-difluoromethylpyrazolecarboxamide fungicides, compositions and use
Abstract
Novel
3-difluoromethyl-1-methyl-N-(substituted-indane-4-yl)pyrazole-4-carboxamid
es useful as fungicides, particularly effective in alleviating infections
in diseased plants.
Inventors:
|
Graneto; Matthew J. (St. Louis, MO);
Phillips; Wendell G. (Glencoe, MO)
|
Assignee:
|
Monsanto Company (St. Louis, MO)
|
Appl. No.:
|
725151 |
Filed:
|
July 3, 1991 |
Current U.S. Class: |
514/406; 548/333.5 |
Intern'l Class: |
A01N 043/56; C07D 231/14 |
Field of Search: |
548/378
514/406
|
References Cited
U.S. Patent Documents
4742074 | May., 1988 | Nishida et al. | 548/378.
|
Primary Examiner: Ramsuer; Robert W.
Attorney, Agent or Firm: Bonner; Grace L., Beck; George R., Stanley; Howard C.
Parent Case Text
This application is a continuation-in-part of co-pending application Ser.
No. 07/646,899, filed Jan. 28, 1991 abandoned.
Claims
We claim:
1. A compound of the formula
##STR3##
wherein R is hydrogen or methyl.
2. 3-Difluoromethyl-l-methyl-N-(1
,1,3-trimethylindane-4-yl)pyrazole-4-carboxamide.
3. Fungicidal compositions comprising a compound of claim 1 and an
agronomically acceptable carrier.
4. The fungicidal composition of claim 3 wherein the compound is
3-difluoromethyl-1-methyl-N-(1,1,3-trimethylindane-4-yl)pyrazole-4-carboxa
mide.
5. A method of controlling fungal disease of a plant comprising applying a
compound of claim 1 to the plant locus.
6. The method of claim 5 wherein said compound is
3-difluoromethyl-1-methyl-N-(1,1,3-trimethylindane-4-yl)pyrazole-4-carboxa
mide.
7. The method of claim 6 wherein said plant locus is the seed of said
plant.
8. The method of claim 6 wherein said plant locus is the foliage of said
plant.
9. The method of claim 6 wherein said plant locus is the rhizosphere of
said plant.
10. A method of alleviating fungal disease of a plant comprising applying a
compound of claim 1 to the locus of a diseased plant.
11. The method of claim 10 wherein said compound is
3-difluoromethyl-1-methyl-N-(1,1,3-trimethylindane-4-yl)pyrazole-4-carboxa
mide.
12. The method of claim 11 wherein said fungal disease is caused by a
species of Botrytis, Alternaria, or Venturia.
13. The method of claim 12 wherein said fungal disease is caused by
Botrytis cinerea and said diseased plant is grape vine.
14. The method of claim 11 wherein the locus of said plant is the foliage.
15. The method of claim 11 wherein the locus of said plant is the fruit.
16. The method of claim 11 wherein the locus of said plant is the stem.
17. The method of claim 11 wherein the locus of said plant is substantially
the whole plant above the soil.
Description
FIELD OF THE INVENTION
The present invention provides novel
3-difluoromethyl-1-methyl-N-(substituted-indane-4-yl)pyrazole-4-carboxamid
es and their use as fungicides.
BACKGROUND OF THE INVENTION
Fungicides for control of agricultural diseases may be used for
preventative applications, for example, as a seed treatment, or for
curative applications, applied to growing plants already infected with a
fungal disease. An efficacious curative fungicide may completely cure the
disease, that is, rid the plant of the fungal infection, or it may
alleviate the infection to such a degree that plant growth and/or crop
yield are not unacceptably inhibited by the disease.
Other carboxamide fungicides are known in the art. U.S. Pat. No. 4,742,074,
issued May 3, 1988, to Nishida et al., discloses various
N-(substituted-indanyl)pyrazole-4-carboxamides useful as fungicides for
various agronomic diseases. Included is
1-methyl-3-trifluoromethyl-N-(1,1,3-trimethylindane-4-yl)pyrazole-4-carbox
amide, described as useful against rice sheath blight (preventative and
curative), brown rust of wheat (curative), and apple scab disease
(preventative). However, there remains a need in the art for superior
fungicides, particularly for curative applications for which a high level
of systemic activity is highly advantageous.
It is therefore an object of this invention to provide compounds having a
broad spectrum of activity against fungal diseases of plants. It is a
further object of this invention to provide compounds having a high level
of effectiveness in curing fungal diseases in affected plants. It is
another object of this invention to provide compounds that readily move
through a diseased plant after application to another part of th e plant,
e.g., its leaves, fruit, or stems. Further, it is an object of this
invention to provide methods of preventing and, more importantly, curing
fungal diseases of plants at comparatively lower application rates,
resulting in lower residues in the plants and the environment.
SUMMARY OF THE INVENTION
Therefore, the present invention comprises the compounds having the
structure
##STR1##
wherein R is hydrogen or methyl; compositions containing these compounds,
and methods of using them to control agricultural fungal diseases,
including curing or alleviating infections.
DETAILED DESCRIPTION OF THE INVENTION
The preferred compound of the present invention is
3-difluoromethyl-1-methyl-N-(1,1,3-trimethylindane-4-yl)pyrazole-4-carboxa
mide, which has the structure
##STR2##
Related compounds, such as
3-difluoromethyl-N-(1,1,3-trimethylindane-4-yl)pyrazole-4-carboxamide and
3-difluoromethyl-1-ethyl-N-(1,1,3-trimethylindane-4-yl)pyrazole-4-carboxam
ide, as well as their 1,1-dimethylindane analogs, are also useful as
fungicides.
The compounds of the present invention are prepared by reacting
3-difluoromethyl-1-methyl-4-pyrazole carbonyl chloride with the
appropriate 4-aminoindane under amide-forming conditions. This pyrazole
carbonyl chloride can be prepared by known methods using ethyl
difluoroacetoacetate, triethyl-orthoformate, and methyl hydrazine to form
the carboxylic ester, which is easily converted to the acid chloride.
Details of such a reaction are given in the following example. This example
is illustrative only and not meant to be limiting in any way.
EXAMPLE 1
Synthesis of
3-difluoromethyl-1-methyl-N-(1,1,3-trimethylindane-4-yl)pyrazole-4-carboxa
mide.
Ethyl difluoroacetoacetate, 44.9 g (0.27 mole), obtained from Starks
Chemicals, was mixed with triethylorthoformate, 54.3 mL (0.33 mole), and
80 mL acetic anhydride. The mixture was refluxed for 2 hours and then
heated to approximately 140.degree. C. to distill off volatiles. It was
held at that temperature for 2 hours and allowed to cool. It was then
distilled under reduced pressure to yield 47.8 g of a light yellow oil.
To this oil was added 200 mL of ethanol and the mixture held at
10.degree.-15.degree. C. while methyl hydrazine, 11.7 mL (0.22 mole), in
ethanol, was added dropwise. After addition was complete, the mixture was
refluxed for 11/2 hours and allowed to cool. The mixture was concentrated
under vacuum. Methylene chloride and 2 N HCl were added. The methylene
chloride layer was separated and dried over magnesium sulfate. The solvent
was removed under vacuum and the crude product recrystallized from toluene
to yield a light yellow solid, 32.4 g. m.p. 25.degree.-27.degree. C. This
was identified as ethyl 3-difluoromethyl-1-methyl-4-pyrazole carboxylate.
This ester was treated with 64 mL of 2.5 N sodium hydroxide, and the
resulting salt acidified to yield the acid, 24.5 g.
This pyrazole carboxylic acid was treated with oxalyl chloride, 15.2 mL
(0.174 mole), in toluene, and a few drops of dimethylformamide was added.
The mixture was concentrated under reduced pressure to yield the carboxyl
chloride as a light amber oil, 26.9 g.
To this acid chloride, in 150 mL methylene chloride, at 0.degree. C., was
added dropwise a solution of
2,3-dedihydro-1,1,3-trimethyl-1H-inden-4-amine, 24.9 g (0.142 mole), and
19.8 mL (0.142 mole) triethylamine, dissolved in 50 mL methylene chloride.
This mixture was stirred overnight at room temperature. It was then washed
once with water and twice with 200 mL 2 N HCl and dried over magnesium
sulfate. The solvent was removed under reduced pressure to yield a solid
which was recrystallized from toluene and washed with hexane to yield 34.2
g of the title compound as a white solid. m.p. 131.degree.-134.degree. C.
The other compound of the present invention may be similarly prepared.
The compounds of the present invention may be used as is without adding any
other components, but generally, they are formulated into emulsifiable
concentrates, wettable powders, suspension formulations, granules, dusts,
liquids and the like by mixing with a solid or liquid carrier, a surface
active agent and other auxiliaries for formulation.
The content of a compound of the present invention contained as an active
ingredient in these formulations is 0.1 to 99.9%, preferably 0.2 to 80% by
weight, and more preferably 2 to 50% by weight. The concentration of the
active compound in the spray solutions as they are applied to growing
plants will be much less, from about 10 ppm up to about 1000 ppm.
The exact amount of active ingredient per hectare to be employed in the
treatment or prevention of disease is dependent upon various factors,
including the plant species and stage of development of plants and
disease, the amount of rainfall, and the specific adjuvants employed. In
foliar applications a dosage of from about 30 to about 2000 g/ha,
preferably from about 60 to about 250 g/ha, is usually employed. In soil
applications a dosage of from about 100 to about 2000 g/ha, preferably
from about 250 to about 500 g/ha is usually employed. Lower or higher
rates may be required in some instances. One skilled in the art can
readily determine from this specification, including the following
examples, the optimum rate to be applied in any particular case.
The solid carriers include for example fine powders or granules of kaolin
clay, attapulgite clay, bentonite, acid clay, pyrophyllite, talc,
diatomaceous earth, calcite, corn starch powder, walnut shell powder,
urea, ammonium sulfate, synthetic hydrated silicon dioxide, and the like.
The liquid carrier includes for example aromatic hydrocarbons such as
xylene, methylnaphthalene and the like, alcohols such as isopropanol,
ethylene glycol, cellosolve and the like, ketones such as acetone,
cyclohexanone, isophorone and the like, vegetable oils such as soybean
oil, cotton seed oil and the like, dimethyl sulfoxide, acetonitrile, water
and the like.
The surface active agents used for emulsification, dispersion, wetting,
etc, include for example anionic surface active agents, such as salts of
alkyl sulfate, alkyl or aryl sulfonates, dialkylsulfo-succinates, salts of
polyoxyethylene alkyl aryl ether phosphoric acid esters, or
naphthalenesulfonic acid/formalin condensates, etc, and nonionic surface
active agents, such as polyoxyethylene alkyl ether, polyoxyethylene
polyoxypropylene block copolymers, sorbitan fatty acid esters, or
polyoxyethylene sorbitan fatty acid esters, etc. The auxiliaries for
formulation include for example lignosulfonates, alginates, polyvinyl
alcohol, gum arabic, and CMC (carboxymethyl cellulose).
The compounds of the present invention may also be combined with other
fungicides, plant growth regulators, fertilizers, herbicides, and
insecticides. Penetrating agents, to increase systemic activity may also
be added to the compounds of the present invention.
Diseases for which the compounds of the present invention may be used
include, but are not limited to, those caused by species of Rhizoctonia.
Botrytis, Alternaria, Cercosporidium, Pseudocercosporella, Puccinia, and
Venturia.
Crops on which the compounds may be used include, but are not limited to,
cereals, for example, wheat and rice; fruits, for example, apples and
grapes; vegetables, for example, tomatoes; oil-producing crops, for
example, peanuts, soybeans, and oilseed rape; and turf. Application
methods to be used in fungal control on plants include, but are not
limited to, direct application to the body of the plant by spraying or
direct application means; soil treatment prior to or at the time of
planting, or at any time during the life of the plant; and application to
the seed o seed pieces prior to or at the time of planting. The latter two
means expose the rhizosphere of the plant to the treatment compound.
It has surprisingly been found that the compounds of the present invention
have superior fungicidal properties, particularly for curative
applications, and more particularly for foliar, fruit, or stem
applications for curative needs. While not wishing to be bound by this
theory, it is possible that the difluoromethyl substituent provides better
uptake of the compound and better movement throughout the plant when
applied by contact with the foliage, fruit, or stems of the diseased
plant. When such an application is made by spraying, the contact will
generally be made with substantially the whole body of the plant above the
soil.
The advantage of improved curative properties is in the lower use rates
that are required to treat diseased plants. This results in significantly
lower residues of the fungicide in the plant and its foliage, seed, or
fruit, and in the environment. An improved curative fungicide also
provides the advantage of reducing or eliminating the need for
preventative applications of fungicides which may also reduce the level of
pesticide residues in crops and the environment.
The compound prepared as in Example 1, hereinafter designated Compound A,
has been tested for fungicidal effectiveness in a variety of tests,
including both preventative and curative application methods. It has been
compared to the compound of U.S. Pat. No. 4,742,074, mentioned above,
believed to be the closest compound of the prior art. This known
fungicide, hereinafter designated Compound B, was prepared according to
Synthesis Example 8 (Compound 19) of that patent, the full text of which
is incorporated herein by reference. The following examples describe the
tests conducted and the results thereof. As demonstrated in Examples 2
through 7, Compound A of the present invention is superior to the prior
art compound in curative applications to the plant foliage, fruit, or
stems.
EXAMPLE 2
Test for curative activity against apple scab.
Young apple plants (cultivar: McIntosh) are inoculated with Venturia
inaequalis, 100E6 spore/mL, and placed in a mist chamber at 20.degree. C.
At 24, 48, or 72 hours after inoculation, four plants for each treatment
level are sprayed with 12 mL of an acetone/water formulation of 20, 100,
or 500 ppm of the test compound(s). Each plant is evaluated at 17 and 24
days post-infection for the level of disease severity.
The results of the average percent disease for the four plants per
treatment level are reported in Table 1, at 17 days post-infection, and
Table 2at 24 days, Compound A was much more effective at 100 ppm than
Compound B at 500 ppm and approximately as effective at 20 ppm as Compound
B at 500 ppm.
TABLE 1
______________________________________
PERCENT
TREATMENT DISEASE SEVERITY
COMPOUND RATE (ppm) 24 HR 48 HR 72 HR
______________________________________
A 500 0.0 2.0 2.0
100 0.0 6.0 1.0
20 3.0 4.0 8.0
B 500 4.0 6.0 26.0
100 6.0 14.0 44.0
20 3.0 22.0 33.0
Control -- 50.0 88.6 81.5
______________________________________
TABLE 2
______________________________________
PERCENT
TREATMENT DISEASE SEVERITY
COMPOUND RATE (ppm) 24 HR 48 HR 72 HR
______________________________________
A 500 1.0 2.0 9.0
100 4.0 4.9 9.1
20 10.2 34.3 61.9
B 500 68.1 43.8 34.3
100 83.8 61.0 34.3
20 36.6 65.8 87.4
Control -- 90.5 94.0 87.4
______________________________________
EXAMPLE 3
Test for curative activity against tomato early blight.
Seedling tomato plants (cultivar: Rutgers) in 3" pots are inoculated with
Alternaria solani, 5E4 spores/mL, and maintained in a mist chamber. At 24
hours after inoculation, five plants per treatment level are sprayed with
10 mL of solution containing 1000, 500, 100, and 20 ppm of the test
compounds. At 5 days post-inoculation each plant is evaluated for the
level of disease, and the percent control, compared to an inoculated,
untreated control, is calculated.
The results of this test are shown in Table 3. Compound A is clearly
superior to Compound B, with 20 ppm of Compound A demonstrating more
curative activity than 1000 ppm of Compound B.
TABLE 3
______________________________________
TREATMENT
COMPOUND RATE (ppm) PERCENT CONTROL
______________________________________
A 1000 90
500 90
100 92
20 73
B 1000 54
500 42
100 62
20 57
Control -- 0
______________________________________
EXAMPLE 4
Test for curative activity against vine grey mold.
Grape berries are placed one per well in 12-well plates and each inoculated
with Botrytis cinerea, 1 mL of 10E6 spores/mL. After 24 hours the
incubation in temporarily interrupted for treatment with 1 mL of an
acetone/water formulation of 1000, 500, or 200 ppm of the test compounds.
The plates are kept in a dark incubator at 20.degree. .C for seven days
and the severity of the disease evaluated by the following scale:
0 = No disease
1 = Mild disease
2 = Moderate disease
3 = Severe disease
The results of this test, reported as the average of five berries per
treatment level are shown in Table 4. Compound A was as effective at 200
ppm as Compound B at 1000 ppm.
TABLE 4
______________________________________
TREATMENT
COMPOUND RATE (ppm) DISEASE RATING
______________________________________
A 1000 0.5
500 1.4
200 2.0
B 1000 1.9
500 2.2
200 2.4
Control -- 3.0
______________________________________
EXAMPLE 5
Test for curative activity against wheat leaf rust.
Young wheat plants (cultivar: Hart) are grown in 3" pots and inoculated at
the two leaf stage with Puccinia recondita, 2 mL of 5E4 spores/mL. 48
hours later each plant is sprayed with 2 mL of an
acetone/water/Tween.RTM.20 formulation containing 100, 20, 5, or 1 ppm of
the test compounds. After 10 days in the growth chamber at 21.degree. C.,
each plant is evaluated for disease level and the percent disease control
compared to an inoculated, untreated control is calculated.
The results of this test, reported as the average of five replicates, are
shown in Table 5. The differences between the two test compounds were
statistically significant at 5 ppm, Compound A being superior.
TABLE 5
______________________________________
TREATMENT
COMPOUND RATE (ppm) PERCENT CONTROL
______________________________________
A 100 100
20 100
5 99.9
1 69.3
B 100 100
20 100
5 95.5
1 58.8
Control -- 0
______________________________________
EXAMPLE 6
Test for curative activity against wheat true eyespot.
Mature wheat plants (cultivar: Slepjner) in 2.25" pots are inoculated with
Pseudocercosporella herpotrichoides, 2 mL of 3E6 spores/mL. Five days
later nine plants per treatment level are sprayed with an
acetone/water/Tween.RTM.20 formulation containing 1000, 500, or 250 ppm of
the test compounds. After 5 weeks in the growth chamber each plant is
evaluated for disease and the percent disease control compared to an
inoculated, untreated control is calculated.
The results of this test are shown in Table 6. Compound A was as effective
at 250 ppm as Compound B was at 1000 ppm.
TABLE 6
______________________________________
TREATMENT
COMPOUND RATE (ppm) PERCENT CONTROL
______________________________________
A 1000 96
500 83
250 83
B 1000 83
500 77
250 63
Control -- 0
______________________________________
EXAMPLE 7
Test for curative activity against Alternaria leaf spot of oil seed rape.
Oilseed rape seedlings (cultivar: Bienvenu) are grown in 7 cm pots and at
the first leaf stage are inoculated with Alternaria brassicae Alternaria,
2 mL of 2E4 spores/mL per pot. After 24 hours, nine plants per treatment
level are sprayed with an acetone/water/Tween.RTM.20 formulation
containing 1000, 500, or 300 ppm of the test compounds. After 7 days, each
plant is evaluated for disease severity and the percent disease control
compared to an inoculated, untreated control is calculated.
The results of three repetitions of this test are shown in Tables 7A, B,
and C. Compound A was superior to Compound B in all tests, exhibiting a
two- to three-fold increase in effectiveness.
TABLE 7A
______________________________________
TREATMENT
COMPOUND RATE (ppm) PERCENT CONTROL
______________________________________
A 1000 90
500 77
300 100
B 1000 77
500 57
300 67
Control -- 0
______________________________________
TABLE 7B
______________________________________
TREATMENT
COMPOUND RATE (ppm) PERCENT CONTROL
______________________________________
A 500 100
300 72
B 500 72
300 33
Control -- 0
______________________________________
TABLE 7C
______________________________________
TREATMENT
COMPOUND RATE (ppm) PERCENT CONTROL
______________________________________
A 1000 77
500 66
250 43
B 1000 43
500 57
250 23
Control -- 0
______________________________________
EXAMPLE 8
Test against oilseed rape dark leafspot in vitro.
Inhibition of Alternaria brassicae is measured in vitro for each of the
test compounds. Each compound is incorporated in potato dextrose agar at
10, 1, or 0.1 ppm. Each plate is inoculated and the radial growth of the
fungus is measured after seven to ten days. The average growth for two
plates per treatment level is obtained and the percent control compared an
untreated plate calculated.
The results of this test are shown in Table 8. Compound A provided superior
fungal inhibitation.
TABLE 8
______________________________________
TREATMENT
COMPOUND RATE (ppm) PERCENT CONTROL
______________________________________
A 10 100
1 68
0.1 41
B 10 71
1 58
0.1 28
Control -- 0
______________________________________
EXAMPLE 9
Test for preventative activity against oilseed rape dark leafspot.
The method of Example 7 was followed except that the plants are sprayed
with the test compounds one day prior to inoculation. Disease control is
evaluated seven days post-infection. The results of this test are shown in
Table 9. Compound A was more effective at 500 ppm than Compound B was at
1000 ppm.
TABLE 9
______________________________________
TREATMENT
COMPOUND RATE (ppm) PERCENT CONTROL
______________________________________
A 1000 84
500 78
250 56
B 1000 69
500 50
250 29
Control -- 0
______________________________________
EXAMPLE 10
Test for preventative activity against vine grey mold.
The method of Example 4 is followed except that the compounds are applied
at the given treatment levels prior to inoculation. Disease severity is
evaluated at 7 days post-infection.
The results of two repetitions of this test are shown in Tables 10A and
10B. They are reported as the average of five berries per treatment level.
Compound A demonstrated a two-to five-fold improvement in activity over
Compound B. The results of a third test, wherein the berries are coated
with the test compound mixed with agarose and only four replicates per
treatment level are used, are reported in Table 10C. Compound A was more
effective at 125 ppm as Compound B was at 500 ppm.
TABLE 10A
______________________________________
TREATMENT
COMPOUND RATE (ppm) DISEASE RATING
______________________________________
A 1000 0.4
500 0.7
200 0.9
B 1000 0.7
500 1.0
200 1.2
Control -- 3.0
______________________________________
TABLE 10B
______________________________________
TREATMENT
COMPOUND RATE (ppm) DISEASE RATING
______________________________________
A 1000 0
500 0.1
200 0.5
B 1000 1.0
500 1.6
200 2.3
Control -- 2.5
______________________________________
TABLE 10C
______________________________________
TREATMENT
COMPOUND RATE (ppm) DISEASE RATING
______________________________________
A 500 0.8
250 1.8
125 1.8
B 500 3.0
250 2.8
125 3.0
Control -- 3.0
______________________________________
EXAMPLE 11
Test for preventative activity against peanut white mold.
Peanut plants, 12 to 14 days old, are grown in 7.65 cm.sup.2 pots. Each
plant, including the soil surface, is sprayed with 2 mL of a
water/acetone/Tween.RTM.20 formulation containing 500, 100, 20, 5, or 1
ppm of the test compounds. The next day two grams of a 21-day, dried, oat
seed culture of Sclerotium rolfsii is spread on the surface of the soil in
each pot. After 10 days in the growth chamber, each plant is evaluated for
the level of disease by the following scale and the average of five plants
per treatment level is calculated.
1 = No disease
2 = Slight disease, slight mycelium, no lesion
3 = Moderate disease, mycelium and small lesion
4 = Moderate/heavy disease, mycelium and lesion
5 = Heavy disease, plan
The results of this test are given in Table 11. Compound A exhibited a two-
to five-fold superiority over Compound B.
TABLE 11
______________________________________
TREATMENT
COMPOUND RATE (ppm) DISEASE RATING
______________________________________
A 500 1.0
100 1.2
20 1.4
5 2.4
1 2.8
B 500 1.0
100 1.4
20 2.6
5 3.2
1 4.0
Control -- 4.6
______________________________________
EXAMPLE 12
Field test in peanuts.
Peanut plants are grown in plots 6 feet long by one row. Each treatment
level is applied to four replicate plots. At 30 days after planting, test
compounds are applied to the plants by spraying four times at 14-day
intervals at rates equivalent to 16, 8, 4, or 2 ounces of active
ingredient per acre. For some plots the test compound is mixed with
Penetrator 3.RTM., a surfactant known to enhance activity of systemic
fungicides, at 0.125% v/v. Disease, consisting primarily of late leafspot,
Cercosporidium personatum, is allowed to develop naturally and evaluated
regularly and just prior to harvest. The results of the last evaluation,
reported as the average disease severity of the four plots per treatment
level, are shown in Table 12. Compound A is superior to Compound B and the
activity of Compound A is enhanced by the penetrating agent.
TABLE 12
______________________________________
TREATMENT
COMPOUND RATE (oz/A) DISEASE RATING
______________________________________
A 16 2.4
8 6.1
4 6.9
2 9.6
A + Penetrator 3
8 2.7
4 5.5
2 11.1
B 16 8.8
8 9.2
4 13.1
2 18.8
B + Penetrator 3
8 8.9
4 11.9
2 17.5
Control -- 35.6
______________________________________
EXAMPLE 13
Test for preventative activity against rice sheath blight.
Rice plants, 11 to 15 days old, are gown in 7.65 cm.sup.2 pots. Each plant
in the treatment groups is treated by spraying both the foliage and the
soil surface, each with 2 mL of a water/acetone/Tween.RTM.20 formulation
containing 0.5, 0.1, or 0.02 mg/mL of Compound A. The pots are placed in
flood trays which are filled with water to the soil line. Two days later
approximately two grams of Rhizoctonia solani, grown on a rice grain
inoculum for four to eight weeks, is applied to the base of the rice
plants in each pot. After 7 days in the growth chamber, each plant is
evaluated for the level of disease control as compared to untreated
controls by the following scale and the average of five plants per
treatment level is calculated.
0 = No activity
1 = Low activity
2 = Moderate activity
3 = High activity
The results of this test are given in Table 13.
TABLE 13
______________________________________
Concentration Activity
mg/mL Rating
______________________________________
0.5 3
0.1 3
0.02 3
______________________________________
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